David can still remember his mum making excuses for him because, as a child, he wouldn’t speak to people he didn’t know.

For the first few years after his daughter came along, she was master of the tight-lipped stare. Making no connection with his own childhood, he used to give her a ticking off for what he saw as her rudeness.

He has since apologised. Because now, his grandson does exactly the same thing. Strangers, trying to be nice, get no response from him. But, at home he’s fine.

Having been confused by it in his own childhood and annoyed by it in his daughter’s – and knowing they both grew up to be friendly, well-adjusted people – he now takes the long-term view. When people try talking to Dominic, David simply says: “He’s probably not going to answer. It’s nothing personal. It’s just a family tradition!”